Mechanical pump spacing adjustment system

ABSTRACT

A well string positioner capable of actuation during the vertical reciprocal movement of a well string will, upon actuation, increase or decrease the length of the well string within the tubular. The vertical reciprocal stroke of the power unit of the well is not changed when the well string length within the tubular is changed, and the well string can be adjusted in operation of the well without the need to disassemble the well string. A system for retrofit to a pre-existing pump jack is disclosed, as well as a conventional pump jack with the well string positioner and capability of the system incorporated as manufactured.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Application No.: CA 3,024,398, filed Nov. 16, 2018 and Application No.: CA 3,017,854, filed Sep. 19, 2018, both of which are incorporated herein by reference.

BACKGROUND

Extraction of oil from hydrocarbon-bearing geological formations is a complicated and capital intensive process. Typically, once a well is drilled into an oil-bearing formation, the drilling string is extracted and a tubular or casing finalized in place in the well, through which pumping or extraction tools can be used to extract oil up the well tubular to the wellhead for transport or further processing.

In many cases, where a well is drilled substantially vertically down into the formation, vertical reciprocal pumps and “pump jacks” are used to bring extracted oil to the surface. A typical arrangement of this nature comprises a downhole plunger style pump attached at the distal end of the well string, within the tubular at a pumping location at which perforations in tubular or other means allow for entry of oil from the formation into the tubular and for pumping to the surface of the tubular upon vertical reciprocating motion of the well string and operation of the pump.

This type of pump typically also includes a travelling valve assembly and a standing assembly. Sometimes in optimizing the operating parameters of the pumping system, or to avoid the tapping of the travelling portions of the pump on the bottom of the well or otherwise by stretching or extension of the well string, it is desirable to shorten or lengthen the length of the well string within the tubular. Traditionally one way this has been done is to disassemble the well string and either shorten or lengthen it, to result in an adjustment of the well string. This type of an approach requires shutdown of the well equipment during adjustment, however, so pumping is interrupted, and the need to disassemble much of the equipment at the wellhead to achieve this type of a well string adjustment is also unduly complicated and carries safety and operational risks. If it were possible to come up with a method for the adjustment of the well string length within a well tubular without the need to shorten or lengthen the well string is believed that this would be commercially desirable and accepted.

Another approach which is often used, where it is not desired to disassemble and/or adjust the length of the well string is to shorten or lengthen the stroke of the vertical reciprocating power unit which is used to actuate the well string and the travelling valve assembly of the pump. However, shortening or lengthening the stroke of the vertical reciprocating power unit has a significant effect on the efficiency of the pumping equipment and the pumping yield at the wellhead—if the stroke is shortened, less oil is pumped with each stroke, and if the stroke is lengthened while the pumping volume is potentially increased, there are operational parameter applications to the added weight or volume of oil within the tubular, or otherwise. If it were possible to come up with a method of adjusting the well string within a well tubular without the need to shorten or lengthen the stroke of the vertical reciprocating power unit used, it is believed again this would be a significant commercial benefit and would be widely commercially accepted in the industry.

Any type of an approach to adjusting the well string and oil well which could be adjusted without the need to shut down pumping or oil production would also be very desirable, in order to maintain consistent output from the pump and the well and maximize commercial success.

SUMMARY OF THE INVENTION

As outlined above it is the object of the present invention to provide a system of a method for adjusting the well string length within a well tubular of an oil well, which can be actuated by an operator and a controller as required.

It is the further object of the present invention to provide a system and method for the adjustment of the well string length within a well tubular, in which the well string length could be adjusted without the need to stop operation of the pump, or to disassemble the well string to adjust its length in any way.

It is a further object of the present invention to provide a system and method for the selective adjustment of the well string length within a well tubular of oil well, in which the stroke of a vertical reciprocal power unit used to actuate a typical downhole pump with a travelling valve assembly would not need to be adjusted in any way while the well string length was adjusted.

There are thousands of pre-existing vertical reciprocating oil pumps in operation in oil fields around the world and if it were possible to come up with a retrofit equipment modification to implement a method and approach the present invention namely the ability to adjust the length of the well string within a well tubular while the pump is in operation, and without the need to disassemble the well string or to alter the stroke of the vertical power unit, such an aftermarket modification would be widely deployable, so such an invention would have aftermarket or service market utility in addition to potential as an OEM feature.

The present invention comprises at least a system for retrofit to a pre-existing pump jack, pump jack with the capabilities of the system integrated therein at the time of manufacture, and a method of use of the equipment of the present invention to allow for the adjustment of the well string length within a well tubular of the well. The first embodiment discloses a system for use in the adjustment of the well string length within a well tubular of an oil well, where the oil well itself comprises a well tubular extending downwards from a wellhead at the earth surface to the bottom of the well in a subterranean fluid-producing formation; a well string having a lower end and a top end and extending downward inside the well tubular through a seal on the wellhead; and a downhole plunger-style pump located within the tubular attached to the lower end of the well string. Upon application of vertical reciprocating movement to the well string, a travelling valve assembly will pump oil from the formation up the well tubular to the wellhead. A vertical reciprocating power unit is attached to the well string, which is capable of applying vertical reciprocating motion of the desired stroke length for the plunger to the well string.

The system comprises a well string positioner connecting the top end of the well string to the reciprocating power unit and capable of actuation while the reciprocating power unit is in operation, whereby on actuation of the well string positioner the top end of the well string can be moved up or down through the seal on the wellhead, resulting in the raising or lowering of the well string below the well string positioner and the decrease or increase of the length of the well string within the tubular. A controller capable of actuation by an operator can actuate or engage the well string positioner to adjust the length of the well string within the well tubular as might be desired by the operator of the well.

The well string positioner will modify the length of the well string within the tubular while the vertical reciprocating power unit continues operation without the need to disassemble the well string, and the stroke of the vertical reciprocating power unit does not change when the length of the well string within the tubular is changed in accordance with this method.

The well string positioner could comprise a rotary power source engaging a threaded top end of the well string, which can by rotation and engagement with the threaded end effectively shorten or lengthen, dependent upon the direction of rotation, the well string between the vertical reciprocating power unit and the pump. In other embodiments of the system and method of the present invention the well string positioner could be a linear actuator, such as a hydraulic cylinder, which was capable of achieving the same objective. Both such approaches are contemplated within the scope of the present invention.

The well string positioner in some embodiments would comprise a carrier bar with a bar aperture therethrough through which a threaded portion of the top end of the well string extends, said carrier bar being attached to the reciprocating movement; load-bearing means engaging the threaded portion of the top end of the well string to the carrier bar, such that the vertical movement of the carrier bar will be translated upon the well string; and a bi-directional rotary power means capable of actuation while the reciprocating movement is in operation, whereby on actuation of the rotary power means the threaded portion of the top end of the well string can be moved up or down through the bar aperture, resulting in the raising or lowering of the well string below the carrier bar and the decrease or increase of the length of the well string within the tubular.

The rotary power means used in the embodiments of the system, controller and method of the present invention could comprise hydraulic or electric motors. Any type of a rotary power means will be understood to be within the scope of the present invention in so far as they could be powered or actuated during operation of the vertical reciprocating power unit.

In certain embodiments of the system and method of the present invention, the well string positioner could also be used to rotate the well string, to provide periodic well string rotation within the tubular and the controller could periodically and incrementally rotate the well string in such embodiments.

It is primarily contemplated that the vertical reciprocating power unit of the present invention is a conventional oilfield pump jack although any other type of a vertical reciprocal power unit capable of actuation of the downhole plunger style pump such as is otherwise outlined herein is contemplated to be within the scope of the present invention.

The length of the well string within the tubular can be adjusted during operation of the vertical reciprocating power unit without the need to disassemble the well string, and the stroke of the reciprocal movement does not change when the length of the well string within the tubular is changed. Many variations on the well string positioner and the controller or sensors of the present invention will be understood to those skilled in the art based upon the general scope of the invention outlined elsewhere in this document and any such modifications and permutations of the invention are contemplated within the scope of the present invention.

The top end of the well string of the well might be threaded, and the well string positioner could comprise a rotary power source capable of engaging the threaded top end of the well string and increasing or decreasing the length of the well string within the tubular when actuated. In a more specific embodiment of the well string positioner of the present invention, that component might comprise a carrier bar with a bar aperture therethrough through which the threaded portion of the top end of the well string extends, said carrier bar being attached to the reciprocating movement; load-bearing means engaging the threaded portion of the top end of the well string to the carrier bar, such that the vertical motion of the carrier bar will be translated upon the well string; and a bi-directional rotary power means capable of actuation while the reciprocating movement is in operation, whereby on actuation of the rotary power means the threaded portion of the top end of the well string can be moved up or down through the bar aperture, resulting in the raising or lowering of the well string below the carrier bar and the decrease or increase of the length of the well string within the tubular.

The well string positioner might also comprise a linear actuator such as a hydraulic cylinder or the like which was configured to, on actuation, apply a linear contraction or extension of the well string resulting in the adjustment of the length of the well string within the tubular. Both such approaches are contemplated within the scope of the present invention, both in terms of rotary or linear contraction or expansion of the length of the well string.

The system of the present invention could be preinstalled on a vertical reciprocating pump jack, or could be sold in a kit or as a retrofit item for in market attachment and deployment. All such approaches are contemplated within the scope of the present invention.

Further embodiments of the present invention comprise a vertical reciprocating pump jack for use in oilfield extraction being adapted to allow for adjustment of the well string length within a well tubular of a well. The well itself comprises a well tubular extending downward from a wellhead at the earth's surface, to the bottom of the well within a subterranean fluid producing formation. The well string extends downward inside the well tubular from the top end above the surface, extending through a seal of the wellhead, to the lower end at least a position within the tubular within the fluid producing formation. I downhole plunger style pump as is known to those skilled in the art is located within the tubular and attached at the lower end of the well string. The plunger style pump will be actuated by vertical reciprocating movement of the well string to pump oil from the formation of the well tubular to the wellhead.

The pump jack itself comprises a vertical reciprocating power unit capable of applying vertical reciprocating motion of the desired stroke length for the pump to the well string. The pump jack also includes a well string positioner capable of powered actuation and connecting the top end of the well string to the reciprocating power unit and which, upon actuation, will raise or lower the well string below the well string positioner through the seal on the wellhead, resulting in the decrease or increase of the length of the well string within the tubular. A controller capable of actuation of the well string positioner by an operator is also included. The pump jack of this embodiment, including the well string positioner and controller, can be used to adjust the length of the well string within the well tubular and the positioning of the lower end of the well string within the well tubular during operation of the pump jack, and the length of the well string within the tubular can be adjusted during operation of the vertical reciprocating power unit without the need to disassemble the well string, and the stroke of the reciprocal movement does not change when the length of the well string within the tubular is changed.

As outlined above with respect to the system embodiments of the present invention it is explicitly contemplated that the pump jack of the present invention could engage a threaded top end of the well string, with the well string positioner comprising a rotary power source capable of engaging the threaded top end of the well string and which could alter the length of the well string within the tubular by applying rotary power to the threaded top end of the well string resulting in the raising or lowering of the well string in relation to the wellhead seal, and by extension resulting in the raising or lowering of the lower end of the well string within the tubular. Many different types of rotary power sources are contemplated, primary ones of which comprise a threaded rotary motion which is powered electrically or hydraulically.

It is explicitly contemplated in certain embodiments, the pump jack of the present invention would include a well string positioner that comprises:

-   -   a. a carrier bar with a bar aperture therethrough through which         the threaded portion of the top end of the well string extends,         said carrier bar being attached to the reciprocating movement;     -   b. load-bearing means engaging the threaded portion of the top         end of the well string to the carrier bar, such that the         vertical motion of the carrier bar will be translated upon the         well string; and     -   c. a bi-directional rotary power means capable of actuation         while the reciprocating movement is in operation, whereby on         actuation of the rotary power means the threaded portion of the         top end of the well string can be moved up or down through the         bar aperture, resulting in the raising or lowering of the well         string below the carrier bar and the decrease or increase of the         length of the well string within the tubular.

Certain embodiments of the pump jack of the present invention could incorporate a capability to incrementally rotate the well string within the tubular, and the controller could be used to rotate the well string either periodically and automatically if the controller would facilitate this, or manually actuated by an operator.

In other embodiments of the present invention, the well string positioner could be a linear actuator such as a hydraulic cylinder or the like which was configured, by attachment between the cop jack and the top end of the well string, to apply a linear contraction or extension of the length of the well string within the tubular. Related modifications can be made to the necessary power source and controller to achieve the same objective.

Also disclosed is a method of adjustment of the well string length within a well tubular of a well. The well itself comprises a well tubular extending downward from a wellhead at the earth's surface, to the bottom of the well within a subterranean fluid producing formation. The well string extends downward inside the well tubular from the top end above the surface, extending through a seal of the wellhead, to the lower end at least a position within the tubular within the fluid producing formation. I downhole plunger style pump as is known to those skilled in the art is located within the tubular and attached at the lower end of the well string. The plunger style pump will be actuated by vertical reciprocating movement of the well string to pump oil from the formation of the well tubular to the wellhead.

The method comprises a first step of attaching a vertical reciprocating pump jack to the top end of the well string. The pump jack itself comprises a vertical reciprocating power unit capable of applying vertical reciprocating motion of the desired stroke length for the pump to the well string. The pump jack also includes a well string positioner capable of powered actuation and connecting the top end of the well string to the reciprocating power unit and which, upon actuation, will raise or lower the well string below the well string positioner through the seal on the wellhead, resulting in the decrease or increase of the length of the well string within the tubular. A controller capable of actuation of the well string positioner by an operator is also included. The pump jack of this embodiment, including the well string positioner and controller, can be used to adjust the length of the well string within the well tubular and the positioning of the lower end of the well string within the well tubular during operation of the pump jack, and the length of the well string within the tubular can be adjusted during operation of the vertical reciprocating power unit without the need to disassemble the well string, and the stroke of the reciprocal movement does not change when the length of the well string within the tubular is changed.

The primary operating step of the method of the present invention comprises during the operation of the vertical reciprocating power unit when it is desired to adjust the length of the well string within the tubular, an operator using the controller to actuate the well string positioner to modify the length of the well string within the tubular to a desired length. The length of the well string within the tubular can be adjusted during operation of the vertical reciprocating power unit without the need to disassemble the well string, and the stroke of the reciprocal movement does not change when the length of the well string within the tubular is changed.

Various specific embodiments of the well string positioner could be included in the pump jack of the method disclosed and any specific embodiments of the well string positioner as otherwise outlined in accordance with the apparatus claims and disclosure herein are contemplated within the scope of the method.

It will be understood that there are many variations on the method, system and controller of the present invention as will be obvious to those skilled in the art of oilfield production and control and instrumentation design and any such modifications and variations are intended to be within the scope of the present invention as claimed and outlined herein.

DESCRIPTION OF THE DRAWINGS

To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced. The drawings enclosed are:

FIG. 1 is a schematic drawing of a typical oil well and pumping configuration, for the purpose of demonstrating the interrelation of components in prior art or other installations;

FIG. 2 is a schematic drawing of one embodiment of the system and pump jack of the present invention; and

FIG. 3 is a detail drawing of the components of a well sting positioner as otherwise outlined herein.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

The schematic drawing of FIG. 1 shows the key components of a prior art oil well. The typical well 1 comprises a well tubular 2 extending downwards from a wellhead 3 at the earth surface 4 to the bottom 5 of the well 1 in a subterranean fluid-producing formation 6; a well string 7 being a rod having a lower end 9 and a top end 10 extending downward through a seal 8 on the wellhead 3 inside the well tubular 2; and a downhole plunger-style pump 12 located within the tubular. Upon application of vertical reciprocating movement to the well string 7, a travelling valve assembly 14 will pump oil from the formation up the well tubular 2 to the wellhead 3. A vertical reciprocating power unit 17 is attached to the well string 7, which is capable of applying vertical reciprocating motion of a desired stroke length for the plunger 13 to the well string 7.

System Overview:

FIG. 2 is a schematic diagram of the elements of one system in accordance with the method of the present invention for the automatic adjustment of the well string and oil well. The oil well itself is shown, with the key components thereof labelled similar to those of the earlier oil well demonstrated in FIG. 1.

The well tubular 2 is shown with the well string 7 extending downward therethrough. The vertical reciprocating power unit 17 is shown attached to the top end 10 of the well string 7. The top end 10 of the well string is attached to the vertical reciprocating power unit 17 via a well string positioner 20. In the case shown, the well string positioner 20 comprises a rotary power unit 20A which engages a threaded upper portion 7A of the well string 7 which when actuated will allow for the expansion or contraction of the well string below the well string positioner 20 without any change in the stroke of the vertical reciprocating power unit 17. Well string positioner 20 is attached to the controller 21 and the controller 21 can actuate the rotary power unit 20A as required to increase or decrease the well string in the oil well as desired.

In operation of the system, when it is desired to modify the length of the well string 7 within the tubular, or the positioning of the lower end 9 within the tubular and in relation to the pump 12, the controller 21 is used to actuate the rotary power unit 20A—which is presumed to be a bidirectional rotary power unit which could by engaging the threaded upper portion of the well string 7 rotatably lift or lower the well string 7 in relation to the power unit 20A by rotating in one direction or the other. The controller 21 could simply be a switch or other human interface actuator which an operator of the well could use to activate the rotary power unit 20A in one direction or the other, or in other embodiments of the invention, the controller 21 could be an electronically actuated control which would allow for local or remote computerized control of the system of the present invention. Both such approaches are contemplated within the scope of the present invention and many different types of specific embodiments of the controller 21, all of which are intended to be covered herein, will be understood to those skilled in the art of system controls and oilfield maintenance. Many types of controllers, as outlined herein, could be used from basic locally operated manual operator controls, through to more elaborate either remotely or locally controlled by operators or automatic control systems.

It is explicitly contemplated that the system comprising the well string positioner for connection between the well string and the pump jack, along with the controller, or a pump jack with the well string positioner and controller manufacturer or attached, are both encompassed herein.

Well String Positioner:

As discussed throughout, a key component of the system of the present invention is a well string positioner 20 which is operatively connected to the well string 7 and the vertical reciprocating power unit 17 which will allow for the adjustment of the well string 16 by shortening or lengthening the length of the well string 7 below the well string positioner, resulting in the adjustment of the well string 16 without changing the stroke of the vertical reciprocating power unit 17 could be designed and are all contemplated within the scope of the present invention.

It is specifically contemplated that either a rotary powered or linear actuated well string positioner 20, connected to the controller 21 such that it could be activated to allow for the extension or contraction of the well string 16 as required, is contemplated within the scope of the present invention. A rotary powered well string positioner 20 might comprise a rotary power means 20A engaging a threaded upper portion of the well string 7, with the appropriate yoke or carrier bar 22 attachment system at the upper end thereof, which would allow for the rotary power means 20A on its engagement to raise or lower the well string 7 and result in an attendant adjustment of the well spacing 16. In other embodiments, the well string positioner 20 might be a linear actuator such as a hydraulic cylinder or the like which was capable of effecting the same type of a movement upon the well string 7. Both linear and rotary equipment of this nature is contemplated within the scope hereof.

Where the well string positioner 20 uses a rotary power means to apply lifting or lowering motion to the well string within the tubular, the rotary power means would effectively engage a threaded upper portion of the well string such that rotation of the threaded engagement portion of the rotary power means would in conjunction or coordination with the threaded elements of the well string provide the necessary lifting or lowering motion thereon. It will be understood to those skilled in the art of mechanical system design that in some cases it may be desired to create a means of attachment between a threaded upper portion of the well string and rotary power means that would result in the rotation of the well string when it was lifted or lowered, and other modified approaches could be taken in which the threaded engagement of the two systems would simply results in the lifting or lowering of the well string within the tubular without a rotary motion being applied to string. Both such approaches are contemplated within the scope of the present invention.

FIG. 3 shows a detailed schematic view of one embodiment of a well string positioner 20 within the scope of the present invention—where the rotary power means 20A is a hydraulic motor. Referring to that Figure, a carrier bar 22 and related yoke assembly can be seen which would be assembled between the well string in the vertical reciprocating pump assembly the rotary power means 20A is attached on top of the carrier bar 22 such that the carrier bar will assist in the application of reciprocating vertical power to the well string. The range of pump spacing adjustment defined by the threaded upper end of the well string 7 is also shown—the yoke 23 would be of sufficient length to allow for the entirety of the pump spacing adjustment and threaded portion of the well string to move above the carrier bar 22 during operation of the pump jack without the need for stopping the application of vertical power and/or without the need to disassemble the well string. It was desired to more significantly modify the pump spacing adjustment or the positioning of the well string within the tubular it made in such a circumstance still be necessary to partially or completely disassemble the well string that this would not be the norm within operation of the system and method of the present invention. It will be understood to those skilled in the art oilfield extraction equipment design and maintenance that many different approaches to the overarching invention here could be taken, without departing from the expressed scope and desired intention. Specifically, any type of a similar device which would allow for the pump spacing adjustment to be made within the tubular without the need to stop the reciprocating vertical motion of the well string or to disassemble the well strength except in a larger maintenance or alteration will all be understood to be within the scope of the intended claims and the invention as outlined herein.

The well string positioner 20 along with a controller capable of actuating same is contemplated to comprise one set of embodiments of the present invention, along with another set of embodiments of the present invention comprising the well string positioner 20 of the present invention pre-manufactured or attached to a vertical reciprocating power assembly for use with a well string within a tubular i.e. both retrofit of the equipment of the present invention as well as OEM incorporation of the device are contemplated within the scope of the present invention.

Controller:

As outlined above, the controller in its simplest embodiments might comprise the control by which the application of bidirectional rotary motion to the threaded upper portion of the well string [in embodiments using a rotary power means in the well string positioner] for actuating the bidirectional linear contraction or expansion of the length of the well string [in embodiments using a linear well string positioner and movement means] could be activated or deactivated—something as simple as a switch, or local electrical control for the power device used to effect movement and contraction or expansion below the well string positioner to the well string, are all contemplated within the scope of the present invention. An operator could simply actuate the power means within the well string positioner until the desired alteration of the length of the well string below the well string positioner was effected, with or without the use of sensors or other downhole measurements to determine the appropriate position of the lower end of the well string.

In the embodiment of the well string positioner 20 shown in detail in FIG. 3, it is contemplated that the rotary power source 20A would be a hydraulic motor. Hydraulic connectors 20B are shown—in its simplest embodiment, the controller 21 would be a hydraulic valve capable of providing the necessary hydraulic fluid function to the rotary power source 20A to lift or lower the well string within the tubular. In cases where rotary power was used but an electric motor was used in the place of a hydraulic motor, rather than a hydraulic valve, the controller 21 could simply be an electrical switch capable of applying the necessary power and polarity to the motor to raise or lower the well string within the tubular. Any such type of a straightforward manually actuated controller for use by an operator will be contemplated to be within the scope of the present invention.

It will also be understood that remote controlled embodiments of the controller 21 could be used, whereby the length of the well string within the tubular could be adjusted remotely by an operator without the need for site attendance, or could even be automatically adjusted by a monitoring system capable of automatically actuating the control 21 as required. All such approaches again are contemplated within the scope hereof.

As outlined some embodiments of the controller 21 might also include a network interface whereby the controller 21 could be accessed either locally or remotely via a local or wide area network to provide control inputs, monitor its performance and otherwise, and the addition of such additional components will be understood to be within the scope of the present invention. As well as outlined above, it is specifically contemplated that the hardware of the controller 21 could either be a software enabled configuration of a standard computer at the oil well site, or a purpose built or purpose programmed programmable logic controller or the like could be used as well. Any type of a combination of software and hardware which is capable of achieving the desired and needed steps of the method of the present invention outlined herein will be understood to be contemplated within the scope of the present invention from the perspective of the broadest enablement of the controller element.

In some embodiments of the present invention, where the well string positioner 20 would apply rotary power to the well string to adjust its length within the tubular, the controller and the well string positioner 20 could also be modified to allow for manually initiated or automatically and/or periodically applied rotation to the well string. In some extraction methodologies it is desired to modestly rotate the well string from time to time within the tubular and with a rotary power source being used within the well string positioner 20 this could be affected as outlined elsewhere herein and will be understood to again be contemplated within the scope of the present invention.

Method:

The method of use of the system of the present invention is fairly straightforward. A well as outlined equipped with a vertical reciprocating power unit and a downhole plunger pump would have the well string positioner 20 of the present invention connected between the well string 7 and the reciprocating power means.

In an operational step of the method of the present invention, when it was desired to modify the length of the well string 7 within the tubular or to adjust the positioning of the lower end of the well string 7 within the tubular, the well string positioner 20 would be actuated to apply linear or rotary power to the upper end of the well string, resulting in the increase or decrease of length downhole within the tubular. The method of operation of the present invention is also contemplated and claimed within the scope hereof.

It will be apparent to those of skill in the art that by routine modification the present invention can be optimized for use in a wide range of conditions and application. It will also be obvious to those of skill in the art that there are various ways and designs with which to produce the apparatus and methods of the present invention. The illustrated embodiments are therefore not intended to limit the scope of the invention, but to provide examples of the apparatus and method to enable those of skill in the art to appreciate the inventive concept. Those skilled in the art will recognize that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the scope of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. 

1. A system for use in the adjustment of the well string length within a well tubular of a well comprising: a) a well tubular extending downwards from a wellhead at the earth surface to the bottom of the well in a subterranean fluid-producing formation; b) a well string having a lower end and a top end and extending downward inside the well tubular through a seal at the wellhead to at least a position within the tubular within the fluid-producing formation; c) a downhole plunger-style pump located within the tubular and attached at the lower end of the well string which will be actuated by vertical reciprocating movement of the well string to pump oil from the formation up the well tubular to the wellhead; and d) a vertical reciprocating power unit capable of applying vertical reciprocating motion of the desired stroke length for the pump to the well string; said system comprising: a) a well string positioner capable of powered actuation and connecting the top end of the well string to the reciprocating power unit and which, upon actuation, will raise or lower the well string below the well string positioner through the seal on the wellhead, resulting in the decrease or increase of the length of the well string within the tubular; and b) a controller capable of actuation of the well string positioner by an operator; whereby during operation of the vertical reciprocating power unit, an operator can use the controller to actuate the well string positioner to modify the length of the well string within the tubular; and wherein the length of the well string within the tubular can be adjusted during operation of the vertical reciprocating power unit without the need to disassemble the well string, and the stroke of the reciprocal movement does not change when the length of the well string within the tubular is changed.
 2. The system of claim 1 wherein the top end of the well string is threaded, and the well string positioner comprises a rotary power source capable of engaging the threaded top end of the well string and altering the length of the well string within the tubular by rotary power applied to the threaded end resulting in the raising or lowering of the well string in relation to the wellhead seal.
 3. The system of claim 2 wherein the well string positioner comprises: a. a carrier bar with a bar aperture therethrough through which the threaded portion of the top end of the well string extends, said carrier bar being attached to the reciprocating movement; b. load-bearing means engaging the threaded portion of the top end of the well string to the carrier bar, such that the vertical motion of the carrier bar will be translated upon the well string; and c. a bi-directional rotary power means capable of actuation while the reciprocating movement is in operation, whereby on actuation of the rotary power means the threaded portion of the top end of the well string can be moved up or down through the bar aperture, resulting in the raising or lowering of the well string below the carrier bar and the decrease or increase of the length of the well string within the tubular.
 4. The system of claim 3 wherein the rotary power means comprises a hydraulic motor.
 5. The system of claim 3 wherein the rotary power means comprises an electric motor.
 6. The system of claim 1 wherein the well string positioner can rotate the length of the well string within the tubular, and the controller can be used to rotate the well string.
 7. The system of claim 6 wherein the controller automatically periodically and incrementally rotates the well string.
 8. The system of claim 1 wherein the well string positioner is a linear actuator configured to apply a linear contraction or extension of the length of the well string within the tubular.
 9. The system of claim 1 wherein the vertical reciprocating power unit is a conventional oilfield pump jack.
 10. A vertical reciprocating pump jack for use in oilfield extraction being adapted to allow for adjustment of the well string length within a well tubular of a well comprising: a) a well tubular extending downwards from a wellhead at the earth surface to the bottom of the well in a subterranean fluid-producing formation; b) a well string having a lower end and a top end and extending downward inside the well tubular through a seal at the wellhead to at least a position within the tubular within the fluid-producing formation; and c) a downhole plunger-style pump located within the tubular and attached at the lower end of the well string, which will be actuated by vertical reciprocating movement of the well string to pump oil from the formation up the well tubular to the wellhead; said pump jack comprising: a) a vertical reciprocating power unit capable of applying vertical reciprocating motion of the desired stroke length for the pump to the well string; b) a well string positioner capable of powered actuation and connecting the top end of the well string to the reciprocating power unit and which, upon actuation, will raise or lower the well string below the well string positioner through the seal on the wellhead, resulting in the decrease or increase of the length of the well string within the tubular; and c) a controller capable of actuation of the well string positioner by an operator; whereby during operation of the vertical reciprocating power unit, an operator can use the controller to actuate the well string positioner to modify the length of the well string within the tubular; and wherein the length of the well string within the tubular can be adjusted during operation of the vertical reciprocating power unit without the need to disassemble the well string, and the stroke of the reciprocal movement does not change when the length of the well string within the tubular is changed.
 11. The pump jack of claim 10 wherein the top end of the well string is threaded, and the well string positioner comprises a rotary power source capable of engaging the threaded top end of the well string and altering the length of the well string within the tubular by rotary power applied to the threaded end resulting in the raising or lowering of the well string in relation to the wellhead seal.
 12. The pump jack of claim 11 wherein the well string positioner comprises: a. a carrier bar with a bar aperture therethrough through which the threaded portion of the top end of the well string extends, said carrier bar being attached to the reciprocating movement; b. load-bearing means engaging the threaded portion of the top end of the well string to the carrier bar, such that the vertical motion of the carrier bar will be translated upon the well string; and c. a bi-directional rotary power means capable of actuation while the reciprocating movement is in operation, whereby on actuation of the rotary power means the threaded portion of the top end of the well string can be moved up or down through the bar aperture, resulting in the raising or lowering of the well string below the carrier bar and the decrease or increase of the length of the well string within the tubular.
 13. The pump jack of claim 12 wherein the rotary power means comprises a hydraulic motor.
 14. The pump jack of claim 12 wherein the rotary power means comprises an electric motor.
 15. The pump jack of claim 10 wherein the well string positioner can rotate the length of the well string within the tubular, and the controller can be used to rotate the well string.
 16. The pump jack of claim 15 wherein the controller automatically periodically and incrementally rotates the well string.
 17. The pump jack of claim 10 wherein the well string positioner is a linear actuator configured to apply a linear contraction or extension of the length of the well string within the tubular.
 18. A method of adjustment of the well string length within a well tubular of a well wherein the well comprises: a) a well tubular extending downwards from a wellhead at the earth surface to the bottom of the well in a subterranean fluid-producing formation; b) a well string having a lower end and a top end and extending downward inside the well tubular through a seal at the wellhead to at least a position within the tubular within the fluid-producing formation; and c) a downhole plunger-style pump located within the tubular and attached at the lower end of the well string, which will be actuated by vertical reciprocating movement of the well string to pump oil from the formation up the well tubular to the wellhead; wherein the method comprises: a. attaching a vertical reciprocating pump jack to the top end of the well string, comprising: i. a vertical reciprocating power unit capable of applying vertical reciprocating motion of the desired stroke length for the pump to the well string; ii. a well string positioner capable of powered actuation and connecting the top end of the well string to the reciprocating power unit and which, upon actuation, will raise or lower the well string below the well string positioner through the seal on the wellhead, resulting in the decrease or increase of the length of the well string within the tubular; and iii. a controller capable of actuation of the well string positioner by an operator; b. during the operation of the vertical reciprocating power unit when it is desired to adjust the length of the well string within the tubular, an operator using the controller to actuate the well string positioner to modify the length of the well string within the tubular to a desired length; whereby the well string positioner can be actuated and operated during the operation of the vertical reciprocating power unit without the need to disassemble the well string; and wherein the stroke of the vertical reciprocating power unit does not change when the positioning of the length of the well string within the tubular is changed.
 19. The method of claim 18 wherein the top end of the well string is threaded, and the well string positioner comprises a rotary power source capable of engaging the threaded top end of the well string and altering the position of the length of the well string within the tubular by rotary power applied to the threaded end.
 20. The method of claim 19 wherein the well string positioner comprises: a. a carrier bar with a bar aperture therethrough through which the threaded portion of the top end of the well string extends, said carrier bar being attached to the reciprocating movement; b. load-bearing means engaging the threaded portion of the top end of the well string to the carrier bar, such that the vertical movement of the carrier bar will be translated upon the well string; and c. a bi-directional rotary power means capable of actuation while the reciprocating movement is in operation, whereby on actuation of the rotary power means the threaded portion of the top end of the well string can be moved up or down through the bar aperture, resulting in the raising or lowering of the well string below the carrier bar and the decrease or increase of the length of the well string within the tubular.
 21. The method of claim 20 wherein the rotary power means comprises a hydraulic motor.
 22. The method of claim 20 wherein the rotary power means comprises an electric motor.
 23. The method of claim 19 wherein the well string positioner can rotate the length of the well string within the tubular, and the controller will periodically and incrementally rotate the well string.
 24. The method of claim 19 wherein the well string positioner comprises a linear actuator configured to apply a linear contraction or extension of the length of the well string within the tubular resulting in the adjustment of the length of the well string within the tubular.
 25. The method of claim 19 wherein the vertical reciprocating power unit is a conventional oilfield pump jack. 